End fitting for vapor arc lamps



May 3, 1960 J. PIEGARO END FITTING FOR VAPOR ARC LAMPS Filed March '7, 1958 INVENTOR.

JOSEP H P IEGARO Ku( LLM Jvpa, 1 w) ATT EYS United States Patent() frice.

2 Claims. (Cl. 24U-11.4)

The present invention deals with an end fitting for vapor arc lamps and more particularly with an end fitting for vapor arc lamps of the type employed in the printing of photo-sensitive surfaces, e.g. in blue printing machines.

Vapor arc lamps of the type employed in blue printing machines, e.g. lamps which are characterized by a considerable increase in vapor pressure after ignition, produce elevated temperatures which are detrimental in blue printing machines and a cooling means must be provided to lessen these high temperatures. Cooling drafts or air currents are generally employed for this purpose. However, since an unprotected lamp operating at a voltage high enough to provide maximum efficiency is sensitive to drafts or air currents, a protective envelope is provided. Protective light transmissive envelopes for this purpose are well known in the art.

It is desirable to provide the type of lamps above described, including said protective envelope, as a unit and,

therefore, an end fitting is required to support the lamp unit structure. It is desirable to support the burner envelope with a metal support for maximum strength. However, it has been found that the conventional metal support, after the lamp has been in operation for a while, conducts excessive heat to the burner seal at the end of the quartz tube which is detrimental to the life of the burner.

It is an object of the present invention to provide an end fitting which as a single unit supports an end of an outer envelope and an end of the quartz arc tube contained therein. It is another object of the present invention to provide an end fitting containing a metal support for the arc vessel and which support does not produce excessive heat at the end of said arc vessel. Itis a further object of the present invention to provide a vapor arc discharge device comprising an end fitting of simple structure easily assembled and disassembled. Other objects and advantages of the present invention will become apparent from the description hereinafter following and the drawings forming part hereof in which:

Figure 1 is a side view of a lamp assembly according to the present invention shown partly in section and partly in elevation, and

Figure 2 is an elevational View showing a lamp support member according to the invention.

According to the present invention, an end fitting is provided which permits a lamp assembly, e.g. a lamp assembly or vaporarc discharge device of the type employed in blue printing machines, to be manufactured as a unit and which includes self-contained structures for operation independently of parts of the apparatus, e.g. blue printing machine, to which the lamp assembly is applicable. For example, the lamp assembly of the present invention need only be secured internally of a blue printing machine and plugged into or otherwise electrically connected to electrical terminals contained in said machine. Since the lamp is manufactured as an independent unit, it possesses a flexibility of use because the Y Patent-ed' May 3, 1960 end ttings completely enclose all end structures which enable the lamp to operate with maximum efliciency.

Figure 1 illustrates a tubular quartz vapor arc lamp envelope 1 containing an inert gas, mercury 2, and electrodes 3, and elongated seal elements 4 extending axially outward of the envelope 1. The conductors 5 leading to electrodes 3 are hermetically sealed within the seal elements 4. The lamp is provided with an outer light transmissive envelope 25. Both the inner envelope 1 and outer tubular envelope 25 are assembled as a unit and mounted by means of end fittings 6, which comprise cuplike electrically nonconductive end closures 7, e.g. ceramic end closures, each provided with a rim or tlange 8 at the `open end thereof and which have an overall diameter substantially equal to that of the outer envelope 25. An end of the tubular envelope 25 is mechanically connected to the flange 8 by means of a metal sleeve 9, the sleeve being turned over the flange to provide a groove 10 between the end of the outer envelope 25 and the flange 8 to provide a stop to space the envelope 25 from the flange. The sleeve 9 is heat insulated from the envelope 25 by means of an insulating material 11, e.g. asbestos, therebetween. Having connected the envelope 25 to closure 7 with the sleeve 9, the sleeve is further secured by means of at least one metallic strip 12 and 13 drawn tightly around the sleeve and locked thereon by means of locking means 14 and 15, e.g. a bolt and nut.

The end closure means 7 has a cavity 16 and an annular seat 17 recessed in the open end of the closure means.

In order to mount the inner envelope 1 without the v production of excessive heat localized at the ends of the envelope, there is provided an arc lamp support member S according to the invention and illustrated by Figure 2 which comprises a disc 18 of insulating material with a central aperture 19 formed therethrough. Substantially U-shaped wires 20, 21 and 22 each havinga base B and substantially parallel legs L are mounted on one face of the disc 18 with the free ends of the legs secured to the disc. The U-shaped Wires are circumferentially spaced from each other defining a cage about the aperture 19. The base of each U-shaped wire is preferably curved outwardly of the aperture 19.

The lamp support member S is mounted on the closure member 7 with the disc 18 seated in the annular seat 17, with the U-shaped wires 20, 21 and 22 embracing an end of the arc tube 1, and with the seal element 4 passing through aperture 19 into the cavity 16. The conductor 5 is connected to leads 23 which pass outwardly of the closure member 7 and are connected to terminal contacts 24.

According to the invention, the wire construction supports the lamp and leaves enough space between the wire supports so that the heat developed at the ends of the arc tube can escape, whereby the ends of the arc tube, the f seals and the electrodes operate cooler than if otherwise supported by means of a solid sleeve or like.

While the description of the invention is specific to the illustrations, various modifications are contemplated within the scope of the appended claims.

What is claimed is:

l. In combination, an inner tubular vapor arc discharge lamp having an elongated sealing portion of reduced diameter, an outer tubular light transmissive envelope, a cup-like closure member for supporting the end portions of both the lamp and the envelope, means connecting the open end of the closure member and the end of the outer envelope, an insulating disc having a central aperture closely encompassing the elongated seal portion of said lamp, and a plurality of wire loops each having legs mounted on one face of the disc and spaced from said aperture and a base portion interconnecting said legs,

the insulating disc secured to the oben end of the closure member.

2. In a vapor arc device according to claim 1, cornprisng an annular seat recessed in the open end of said closure member, said disc positioned in said seat.

References Cited in the le of this patent UNITED STATES PATENTS Martt May 26, 1953 Jurick June 25, 1957 Williams Sept. 24, 1957 FOREIGN PATENTS `Great Britain Nov. 24, 1954 ...,...1 www 

